Increasing the flow of oil-wells



LLS. v 11151. 17, 1696 (No Model.) m

1.111.117.1111 DYKE.

- INCREASING THE FLOW 0F OIL WE NITED STATES PATENT OFFICE.

JOI-IN IV. VAN DYKE, OF LIMA, ASSIGNOR OF ONE-HALF TO HERMAN FRASOH, OF CLEVELAND, OHIO.

INCREASING THE FLOW OF OIL-WELLS.

SPECIFICATION forming part of Letters Patent No. 556,651, dated March 17, 1896.

Application filed June 27, 1895. Serial No. 554,182. (No model.)

To a/ZZ whom t may concern:

Be it known that I, JOHN IV. VAN DYKE, a citizen of the United States, residing at Lima, in the county of Allen and State of Ohio, have invented a certain new and useful Improvement in Increasing the Flow of Oil-Wells; and I do declare the following to be a full, clear, and exact description of the invention.

This invention relates to a method of increasing the flow of oil-wells in limestone formations-such, for example, as the oil-wells of the Lima district in Ohio and of certain other parts of the United States and of Canada.

I-Ieretofore it has been customary to increase the iiow in these, as in other wells, by exploding torpedoes therein. The effect of the explosion is to shatter the rock, but this is filled with liquid and the disintegration does not extend far.

The present invention consists in a new and superior method based upon chemical action. In accordance with the new method a chemical re-agent, such as sulphurie acid, which decomposes without substantially dissolving the limestone rock in which the well isis in-` troduced thereinto in sufficient quantity to exert a substantial effect upon the walls of the well. From about one thousand to two thousand gallons of sulphuric acid are preferably employed. In order to secure an eX- tended effect not only is the reagent introduced into the cavity of the well, but the reagent in the well is put under strong pressure, which may be that of a high column of liquid in the supply-pipe, so as to be pressed into the rock and made to act upon the same at a distance from the original well-hole. As these wells are ordinarily of great depth, say twelve hundred feet, an enormous pressure may thus be developed, and, if desired, other pressureproducing means may be employed.

It is an advantage to confine the reagent outside the supply-pipe to the lower (or oilyielding) portion of the well-hole. This can be done by a suitably-arranged packer, which shuts of the lower from the upper portion of the hole and prevents the reagent from ascending above the packer.

The reagent seems to act chieiy upon the films which bind together the more solid particles, and thus by disintegrating the rock into a more or less sand-like mass to increase its porosity. As a result of this action a larger territory may be drained, while the oil has a larger surface through which to filter and a more ready access to the well-hole. By using enough acid and pressing it back into the rock long channels can be formed and oil reached thereby which otherwise could not be had without drilling other wells, if at all.

After introducing a suitable quantity of the reagent, it is advantageous to displace it and cause it to penetrate farther into the rock by forcing a neutral or cheap liquid, such as water, into the well, and it is also advantageous in case the acid is not wholly neutralized by the limestone, or generally as a measure of precaution, to introduce an alkaline liquid, preferably milk of lime, to neutralize any trace of acid which may exist..

The advantage of neutralization is to avoid the danger of corroding the subsequentlyused apparatus, either that for cleaning out the well or for pumping. The cleaning out consists in removing the solid subdivided particles of rock which are brought into the wellhole, and may be done with the usual sandpump, the usual drilling-tools being used, if necessary, to loosen any hard sediment which may form. More or less of the liquid which returns to the well-hole would be removed with the said solid particles, but that which is free from the finely-divided solid matter or sandlike particles can be removed by the pumping apparatus, composed of tubing and suckerrod, which is employed to pump the oil.

The insoluble salt of calcium which is formed by the decomposition of the limestone will mainly precipitate and settle at the bottom of the channels which have been cut in 4the rock by the acid. The eifect, notwithstanding such precipitation and retention of the insoluble salt in the said channels, is,

however, sufficient to increase to a useful extent the area drained by the well and to allow the oil more ready access to the wellholes.

The following is a description of what is considered the best mode of carrying out the IOO invention, reference being had to the accompanying drawings, which form part of this specification, and in which- Figure I is a diagram of a well with the supply or reagent-introducing pipe in place, and Fig. II is a detail view illustrating a mode of protecting the said pipe.

The pipe A is provided with a rubber packer B in the rock above the Trenton limestone C in which the well is. It may be enameled or lead-lined pipe, externally coated with enamel or lead below the packer B, or it may be otherwise made proof against corrosion. There is a box D provided with a funnel-shaped bottom to feed the acid to the pipe A. As shown in Fig. II, the pipe A is lined with a tube 2 of soft rubber and covered exteriorly with another soft-rubber tube 3, the lower end of the inner tube being turned back over the pipe A and also the outer tube, and the whole wrapped to prevent ingress of liquid at the joint. The reagent (sulphuric acid) is placed in the box D, which is kept full, so that the pressure of the whole column (of twelve hundred feet, if that be the depth of the well) is exerted upon the acid in the well, which acid is by the pressure and its own corrosive action forced into the rock, greatly increasing its porosity and extending the area drained by the well. Limestone is decomposed with the formation of the practically insoluble sulphate of calcium. As the acid is incapable of holding in solution more than an inconsiderable portion of this salt, the latter will exist as a precipitate which will mainly settle out of the liquid in the channels in the rock, partly obstructing them it is true, but not preventing an in improvement in the yield of oil as the net result of the operation. Vhen as much acid as desired (say one thousand gallons) has gone into the rock, aforcepump is connected with the pipe A and fresh water is forced down to displace the acid in the pipe and rock, and by forcing it still farther into the rock extend the area of its action. After a rest of, say twelve hours, milk of lime is pumped down to neutralize any trace of acid that might exist. The well is then cleaned out and the tubing replaced and the work of pumping oil carried on as usual.

The usual sand-pump may be used in cleaning out, and it may, of course, be employed as often as necessary after pumping is resumed in order to remove solid particles which may be broughtinto the well-hole during the pumping, the tubing being temporarily removed in order to allow the use of the sandpump.

Other reagents which decompose limestone without substantially dissolving the same (the product of the reaction being an insoluble compound) may be used instead of sulphuric acid, although this is preferred by reason of its eliiciency and cheapness.

I claim as my invention or discoveryl. The method of increasing the flow of oilwells in limestone formations, by introducing I into the well a large quantity of a chemical reagent, such as sulphuric acid, which decomposes the rock without dissolving it, and allowing said reagent to act upon the walls of the well; substantially as described.

2. The method of increasing the flow of oilwells in limestone formations, by introducing into the well a large quantity of a chemical reagent, such as sulphuric acid, which decomposes the rock without dissolving it, and subjecting such reagent in the well to strong pressure; substantially as described.

3. The method of increasing the flow of oilwells in limestone formations, by introducing into the well a large quantity of a chemical reagent, such as sulphuric acid which decomposes the rock without dissolving the same, allowing said reagent to act upon the walls of the well, and also introducing a neutral or cheap liquid such as water into the well to force said reagent farther into the rock; substantially as described.

4. The method of'increasing the ow of oilwells in limestone formations, by introducing into the well a large quantity of a chemical reagent, such as sulphuric acid, which decomposes the rock without dissolving it, then introducing into the well a neutral or cheap liquid such as water to force the said reagent farther into the rock, and finally introducing a neutralizing liquid; substantially as described.

5. The method of increasing the flow of oilwells in limestone formations, by introducing into the well a large quantity of a chemical reagent, such as sulphuric acid, which decomposes the rock without dissolving it, coniining said reagent to the lower or oil-yielding portion of the well-hole, and forcing it by pressure into the rock; substantially as described.

6. The method of increasing the flow of oilwells in limestone formations, by introducing into the well a large quantity of a chemical reagent, such as sulphuric acid, which decomposes the rock without dissolving it, forcing it by pressure into the rock, removing the pressure, and cleaning out the solid particles which are brought into the well-hole; substantially as described.

In testimony whereof I aiiix my signature in presence of two witnesses.

JOHN W. VAN DYKE. )Vitnessesz J. G. NEUBAUER, Z. BURGE.

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